OnePlus 9.0.15 broke my LTE on my OP6T

[messypotamia]

A few weeks ago it OTAd 9.0.15 and I just now noticed that it never achieves LTE, only 4G. I didn't notice it until today while I was roaming on Orange F and I had mostly unusable data; while another phone with the same SIM (telekom.de) roamed on Orange F and got great data, and also showed LTE. Though I have two phones on telekom.de SIMs, and both are android 9, the OnePlus now gets crappy or no data while roaming, and I roam the adjacent EU countries frequently and need the OP6T to work properly.
I searched but haven't seen anything that really applies in my situation.
I never guessed I'd have this trouble with this phone; at first I was very pleased with it. Until the last update.
Who else, if anyone, is aware of this? Again, the two phones, side-by-side, same telekom.de SIMs, roaming abroad EU (today was Orange F), one works fine but one (OP6T) no longer is acceptable.
Thank you for your help with this.
We hope OnePlus will fix this or give me my $ back to buy a different phone!
Thank you,
//MP//

 

[Rukbat]

It's more like "OnePlus 9.0.15 broke my LTE indication on my mobile data icon on my OP6T" That's all that happened - since 4G is now LTE, there's no need to say it. If you like, read this, written almost 3 years ago. They're now deploying 5G LTE.

 

[messypotamia]

It's more like "OnePlus 9.0.15 broke my LTE indication [snip]

I would never have even noticed or cared if my OP6T got the same data / voice it got a month ago while roaming in the EU. Like I said my data was close to zero, while my wife's android 9, roaming under the same exact circumstances at the same time (all day long while in France) got great mobile data. 9.0.15 broke something such that Orange F still likes her phone (an Essential PH-1), and can't give my OP6T decent service.
Whiskey. Tango. Foxtrot.
Can anyone tell me how I get a live (English speaking) OnePlus California person on the phone? I can call via my landline for free from here to the US.
Thank you --

 

[messypotamia]

One More Thing -- while roaming -- while the other phone gets either 4G or LTE, my now-9.0.15 OP6T gets either H, or Edge; even when H (4-5 bars) b/w still sucks.